Which is false regarding heparin?

Correct Answer: B

Rationale: B: Stored in mast cells. Heparin is not stored in mast cells; it is synthesized in mast cells and basophils. Heparin is stored in granules within these cells and released upon activation. This is why choice B is false. The other choices are true: A) SubQ injection can lead to hematomas due to its anticoagulant effect, C) Heparin binds to antithrombin III to inhibit thrombin, and D) Protamine sulfate is used as an antidote to heparin overdose by binding to heparin and neutralizing its effects.

Correct Answer: B

Rationale: The correct answer is B: Defects in peripheral proteins. Spherocytosis is a condition characterized by red blood cells with a spherical shape due to defects in the peripheral proteins such as spectrin. This leads to decreased cell flexibility, making the cells more prone to premature destruction in the spleen. Choice A is incorrect because spherocytosis is not caused by abnormal integral proteins. Choice C is incorrect as increased roleaux refers to red blood cells sticking together, not the cause of spherocytosis. Choice D is incorrect as sickle-shaped cells are characteristic of sickle cell anemia, not spherocytosis.

Correct Answer: B

Rationale: The correct answer is B because NHL commonly originates from B cells. B cells give rise to most NHL subtypes, making the B-cell phenotype more common. Choice A is incorrect because RS cells are characteristic of Hodgkin's lymphoma, not NHL. Choice C is incorrect as NHL can involve non-contiguous lymph nodes. Choice D is incorrect as some NHL subtypes can have a leukemic phase.

Correct Answer: A

Rationale: The correct answer is A because basic immunoglobulin structure consists of 2 identical heavy chains and 2 identical light chains. Heavy chains are joined to each other and to light chains by disulfide bonds. This arrangement forms the characteristic Y-shape structure of an antibody. Choices B, C, and D are incorrect because they involve different combinations of heavy and light chains, which do not align with the typical composition of basic immunoglobulin.

Correct Answer: A

Rationale: The correct answer is A: CD3. T-lymphocytes express CD3, a complex of proteins involved in T-cell receptor signaling. CD19 (B cell marker), CD16 (NK cell marker), and C29 are not typically expressed on T-lymphocytes. Therefore, the presence of CD3 is specific to T-cells, making it the correct choice.